From 9e347728c4fe0f0661194243384ac9f61d7a5c73 Mon Sep 17 00:00:00 2001 From: Guenter Roeck Date: Thu, 12 Dec 2019 09:14:34 -0800 Subject: hwmon: (pmbus) Detect if chip is write protected If a chip is write protected, we can not change any limits, and we can not clear status flags. This may be the reason why clearing status flags is reported to not work for some chips. Detect the condition in the pmbus core. If the chip is write protected, set limit attributes as read-only, and set the flag indicating that the status flag should be ignored. Signed-off-by: Guenter Roeck --- drivers/hwmon/pmbus/pmbus.h | 11 +++++++++++ drivers/hwmon/pmbus/pmbus_core.c | 12 ++++++++++++ 2 files changed, 23 insertions(+) (limited to 'drivers/hwmon') diff --git a/drivers/hwmon/pmbus/pmbus.h b/drivers/hwmon/pmbus/pmbus.h index d198af3a92b6..90d6c9e23d5f 100644 --- a/drivers/hwmon/pmbus/pmbus.h +++ b/drivers/hwmon/pmbus/pmbus.h @@ -22,6 +22,8 @@ enum pmbus_regs { PMBUS_CLEAR_FAULTS = 0x03, PMBUS_PHASE = 0x04, + PMBUS_WRITE_PROTECT = 0x10, + PMBUS_CAPABILITY = 0x19, PMBUS_QUERY = 0x1A, @@ -225,6 +227,15 @@ enum pmbus_regs { */ #define PB_OPERATION_CONTROL_ON BIT(7) +/* + * WRITE_PROTECT + */ +#define PB_WP_ALL BIT(7) /* all but WRITE_PROTECT */ +#define PB_WP_OP BIT(6) /* all but WP, OPERATION, PAGE */ +#define PB_WP_VOUT BIT(5) /* all but WP, OPERATION, PAGE, VOUT, ON_OFF */ + +#define PB_WP_ANY (PB_WP_ALL | PB_WP_OP | PB_WP_VOUT) + /* * CAPABILITY */ diff --git a/drivers/hwmon/pmbus/pmbus_core.c b/drivers/hwmon/pmbus/pmbus_core.c index 8470097907bc..2c196eddbb8d 100644 --- a/drivers/hwmon/pmbus/pmbus_core.c +++ b/drivers/hwmon/pmbus/pmbus_core.c @@ -1088,6 +1088,9 @@ static struct pmbus_sensor *pmbus_add_sensor(struct pmbus_data *data, snprintf(sensor->name, sizeof(sensor->name), "%s%d", name, seq); + if (data->flags & PMBUS_WRITE_PROTECTED) + readonly = true; + sensor->page = page; sensor->reg = reg; sensor->class = class; @@ -2141,6 +2144,15 @@ static int pmbus_init_common(struct i2c_client *client, struct pmbus_data *data, if (ret >= 0 && (ret & PB_CAPABILITY_ERROR_CHECK)) client->flags |= I2C_CLIENT_PEC; + /* + * Check if the chip is write protected. If it is, we can not clear + * faults, and we should not try it. Also, in that case, writes into + * limit registers need to be disabled. + */ + ret = i2c_smbus_read_byte_data(client, PMBUS_WRITE_PROTECT); + if (ret > 0 && (ret & PB_WP_ANY)) + data->flags |= PMBUS_WRITE_PROTECTED | PMBUS_SKIP_STATUS_CHECK; + if (data->info->pages) pmbus_clear_faults(client); else -- cgit v1.2.3